A novel, point-of-care test for lithium levels: description and reliability.

BACKGROUND Lithium is a highly effective agent for numerous psychiatric disorders but requires therapeutic monitoring because of its narrow therapeutic index. This article describes a novel instant blood test that will facilitate the routine monitoring process. METHOD This instant blood test allows the clinician to take a finger-stick sample of whole blood and determine the plasma lithium level in a 2-minute period. This new test is compared with standard laboratory measurements for lithium in human subjects. The reliability of the new test is reported as agreement with standard laboratory values in 3 studies involving a total of 269 subjects. RESULTS The test demonstrates extremely high reliability (r = 0.962, 0.928, 0.983 for studies 1-3, respectively) for the measurement of serum and plasma lithium levels as compared with standard laboratory measures. CONCLUSION This new test is reliable and offers unique advantages over standard laboratory procedures for measuring lithium levels in patients.